I need to buy a nic that I want to eventually (~3 months) re-use for a VM server deployment that will need to support heavy network I/O. Server is a Xeon Gulftown/Westmere-EP.

Intel has server NICs that support VMDc, VMDq, or both.

Which is the difference?

Which do I want? They both seem to deal with the problem of doing per-VM segmentation at the NIC level, but I don't know which technology better.

See VMDc: http://www.intel.com/network/connectivity/solutions/vmdc.htm

See VMDq: http://blogs.intel.com/idf/2008/08/vmdq_and_vmware_netqueue_will.php?wapkw=(vmdq)

Thank you

1 Answer 1


VMDc is for assigning a single VM its own personal NIC, which breaks all the fun stuff of VMs like live migrations.

VMDq is an extension of processing offload and buffering, often called NetQueue. Go ahead and get that, though it's not going to be a huge boost unless you have some major workloads on the NICs.

  • I do intend to run heavy network I/O in these VM's. For VMDc do you mean a full physical nic per VM, or a single "virtual" nic? For VMDq, how benifit does that bring to a VM?
    – nonot1
    Commented Mar 23, 2011 at 20:15
  • VMDc - full physical NIC assigned to a VM (a la VT-d). VMDQ - The NIC will pre-route the data packets to take the overhead off of the hypervisor. This doesn't really become an issue until you have 10Gbit NICs, though.
    – Hyppy
    Commented Mar 23, 2011 at 20:23
  • 1
    See intel.com/network/connectivity/solutions/vmdc.htm Almost seems like VMDc can do 1+ VM per NIC. Can you clarify? How is this different from VMDq?
    – nonot1
    Commented Mar 23, 2011 at 21:58

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